Why no temperature sensor on 12V battery in Prii?

Hi Everyone

I have been recording this PID from OBD2 since Sep 1st 2012 and it seems it is not directly associated with some other temperatures.

In the following graph you can see the evolution of the average temperature in every trip I made for: 12Volt batt temp (blue), room temp (red), HV batt cooling air temp (green) and ambient temp (yellow).



It seems that the 12Volt batt temperature is higher than ambient but lower than room and HV batt cooling air.

Big hugs from Frank

 

I configured the XGauge from Vincent for the aux battery. My observation to and from work today mirrors FrankTiger's, higher than ambient but lower than HV battery or cabin temps.

My thoughts are that since this battery sits in a cavity below the cargo area floor it is somewhat insulated from the cabin temp but would be somewhat higher than outside ambient.

 

Thank you, Vincent for the information. I keyed it into my ScanGauge and low and behold it reads out the temperature. When I first started the car it pretty much read the same as the outside air temp (64f degrees) . Then I made a 12 mile trip on the freeway and back and the reading stayed at a steady 87f degrees. That is pretty much what I would expect. It is apparent that the sensor reads ambient air temp.

 

Just curious, what do you consider to be ambient air temp? The outside air temp was 64f and the reading was steady at 87f, so what do you consider ambient?

 

Rear area Interior temperature under driving conditions in direct sunlight... The surrounding environment in which the battery operates.

 

OK. Do you monitor cabin temps? What I have seen is the aux battery temp is higher than outside ambient but lower than cabin temps. It may very well be the temp of the aux battery cavity.

 

I would attribute the higher battery temperature vs cabin temperature to the rear hatch back light (window) and close proximity of the battery area to the wheel well. I don't think that, that area is not without some influence from road and tire heat.

 

Are you seeing higher battery temps than cabin temps? That is not what FrankTiger or I am seeing.

 

To tell you the truth, haven't been monitoring the cabin temp. I do know, however that cabin temperature couldn't have been 87 degrees. I had the auto A/c set to 68 degrees. Also, unless the car is cold soaked overnight, the cabin temperatures probably wouldn't be consistent throughout the interior. So, I think comparing the cabin and battery temperatures under driving conditions is like comparing Horses and apples. The battery is pretty much insulated from the cabin in that location.

 

Hi everyone

In the following chart you may see the evolution of several temperatures (ºC) in a 51.5Km (32.0 miles) trip.

The thick black curve is the temperature of the Aux Batt which has only one step (from 20ºC to 21ºC) until the last four minutes of the trip in which it has two steps up of 1ºC. However ambient temperature moves down 1ºC in these last four minutes.



I hope you like it.

Big hugs from Frank

 

Hi everyone! The temp sensor of my Toyota Prius cut so the energy monitor stopped working, when I read it on the internet I went back to the car and connected it and it works.